A conventional blackboard may be written with a chalk on the board. However, the dust as spread from the blackboard may cause air pollution for a teacher and the students in a classroom. A so-called xe2x80x9cwhite boardxe2x80x9d may use a marker pen filled with marking ink therein for substituting the conventional chalk for writing on the whiteboard. However, the solvent of the ink within the marker pen will be easily vaporized, still contaminating the air. Once the ink is exhausted or dried, a new pen should be provided to thereby waste money.
The present inventor has found the drawbacks of the conventional writing boards and invented the present reversible colorful writing board and pen.
The object of the present invention is to provide a reversible colorful writing apparatus including a reversible writing board composed of a plurality of coloring picture tubes each filled with a plurality of immiscible coloring liquids in each coloring picture tube and suspended with a miniature magnet within each picture tube, and an inkless writing pen having a stepping-motor control circuit provided within the writing pen; whereby upon moving of the pen on the board, the stepping-motor control circuit will drive the miniature magnet forwardly (or reversely) in each picture tube to drive the immiscible coloring liquids forwardly (or reversely); and upon setting of the magnet at a specific position in the tube, a specific coloring liquid corresponding to such a specific magnet position will be driven to the top surface of the picture tube to display such a specific color on the board.